chemistry final study guide

SI Units

The International System of Units used for measurements.

Base Units

Fundamental measurements like second (s), kilogram (kg), Kelvin (K), and meter (m).

Derived Units

Combinations of base units, such as cubic meter (m³) for volume.

Density

Mass per unit volume; calculated using the formula Volume = Mass / Density.

Dimensional Analysis

A method used to convert between different units.

Celsius to Kelvin Conversion

To convert degrees Celsius to kelvins, add 273.15.

Significant Figures

Digits in a measurement that contribute to its precision.

Accuracy

How close a measurement is to the true value.

Precision

The reproducibility of measurements.

Matter

Anything that has mass and volume.

Physical Properties

Observable properties without changing chemical composition.

Chemical Properties

Properties observed only by changing chemical composition.

Homogeneous Mixtures

Mixtures with uniform composition, like salt-water.

Heterogeneous Mixtures

Mixtures with visible differences in composition, such as sand-water.

Law of Definite Proportions

A compound always contains the same elements in the same mass proportions.

Atomic Number

The number of protons in an atom, determining the element's identity.

Isotopes

Atoms of the same element with different numbers of neutrons.

Mass Number

Total number of protons and neutrons in an atom.

Radioactivity

Spontaneous emission of radiation from an unstable nucleus.

Bohr Model

Model describing electrons orbiting the nucleus at specific energy levels.

Heisenberg Uncertainty Principle

The exact location and momentum of an electron cannot be known simultaneously.

Valence Electrons

Outermost electrons in an atom, crucial for determining chemical behavior.

Periodic Law

Element properties recur periodically when arranged by atomic number.

Atomic Radius

Measure of the size of an atom, increasing down a group and decreasing across a period.

Electronegativity

The ability of an atom to attract electrons in a bond.

Octet Rule

Atoms tend to have eight electrons in their outermost energy level.